Panel-treating process



Filed March 13. 1961 TTOPNEV r' g 3,110,607 Ice Patented Nov. 12, 1963 3,110,607 PANEL-MATEN@ PRUCESS Clifford T. McElroy, 6107 S. Central Ave., Los Angeles, Calif.

Filed Mar. 13, 1961, Ser. No. 95,057 3 Claims. (Cl. 117-8) This invention relates to a process for treating panels, particularly plywood panels, to so condition the outer surface thereof that the same will not become spotted by water and other liquids.

Ordinary plywood panels, unless heavily painted or otherwise provided with a heavy coat that conceals the grain, retain sufiicient porosity so that the same will spot when wetted. Unless solvent-borne coatings are applied to such panel surfaces, the same have no protection from moisture, will absorb the same and lose the initial beauty of their grain by reason of such lack lof protection.

The reason for such absorption properties is that the sanded Vsurfaces of the panels retain extremely soft and flexible minute raised fibers or filaments that, by capillary force, absorb moisture and thereby spot such surfaces of plywood panels. Unless much labor, at high cost, is used for removing these 4capillaries on plywood panels, the same will spot from water.

An object of the present invention is to provide a simple, inexpensive and high production process or method for not `only removing such capillaries but simultaneously providing these surfaces with a resinous facing that embeds such capillaries that will not be totally removed as well as resin-covering the entire surface being treated.

This invention also has for its object to provide a novel, economical and convenient method or process of superior utility.

The invention also comprises novel combinations of method steps, which will appear more fully in the course of the following description of the present method or process the same being based on the accompanying drawing. However, the following specification merely discloses one embodiment of the present invention, and the same is given by way of example only.

In the drawing, like reference characters designate similar parts in the several views.

PIG. 1 is a schematic side elevational view of apparat-us for treating plywood panels to obviate liquid-spotting of the outer surfaces thereof..

FlG. 2 is .a greatly enlarged and fragmentary sectional view showing the surface 4of a panel before the same is subjected to treatment according to the present process.

HG. 3 is a similar view showing the surface at an intermediate point of treatment.

FIG. 4 is a further enlarged and fragmentary sectional View showing the panel surface at the end of the treatment for rendering the same spotting-proof.

The present process comprises, generally, moistening the surface of a panel 5 to be treated to cause the minute surface fibers or filaments 6, by absorption, to swell and rise up from the base surface 7, quickly subjecting such moistened surface to singeing hea-t to burn oii the fibers, thereby reducing them to easily removable ash, then sanding said surface to remove the singed fibers, and repeating the above three steps of the process two, three or more times or until substantially all of the wood fibers have been removed.

The process `contemplates using the moistening liquid as a carrier for a small proportion of acrylate resin such as disclosed in Patent No. 2,753,318 to Maeder dated July 3, 1956, which so coats the finished panel as to completely embed such short lengths of residual Ifibers that san-ding does not remove. The specific resin is not a part of the invention as claimed.

The apparatus shown in FIG. 1 is devised for carrying out the above-described process on a continuous commercial basis so that the same produces panels with non-spotting surfaces at a high production rate and low cost.

The apparatus that .is illustrated, by means of a continuously moving conveyor 8', supported on rollers or the like 9, moves a series of panels 5 along a path for treatment according to the present invention.

A moistener 10, that stores a wetting liquid preferably comprising water with from t-wo percent to five percent of liquid acrylate resin, is provided with a'moistening rol-ler 11 that applies said wetting liquid to the upper surface of the panel 5, as the panel moves along the mentioned path indicated by the arrow 12. The percentage of resin to water may be greater than the five percent mentioned but good results have been obtained with the mentioned maximum, and a larger percentage would not improve the results but would increase the cost of operation. The roller- 11 is a simple means for applying the moistening liquid to be absorbed by the fibers 6 and the same may be applied in other ways, providing a squeegee or doctor blade is used to remove excess applied liquid.

The disclosed apparatus includes a burner 13 that, advantageously, uses an open flame (gas is preferred) to singe or burn off the wetted fibers 6 that, because the same are minute, swell rapidly and rise from the top or base surface '7 of the panel. Since the panel continues to move as described, these wetted fibers are quickly burned off and the liquid on sur-face 7 is as quickly dried, preventing soaking of this surface or any material moisture penetration. By the time the panel moves past the burner i3, it is quite dry and the singed fibers are mostly ash.

A sander 14 is placed so as to sand the dried surface of the panel as .the sa-me continues to move. This step removes the singed fibers which, because they are quite dry and will not lie over fiat against the surface 7, as the original fibers ordinarily do, are removed by the sander in an efiicient manner.

This successive moistening, singeing and sand-ing =of the panel surface 7 -Will greatly improve the smoothness of Isaid surface and will resist spotting by liquid due to the residual fine layer of acrylate resin on said surface. However, to insure that the surface 7 is completely sealed off and such fibers that may remain are totally embedded in acryla-te resin, the above three steps may be repeated one or more times until the surface 7 has built up thereon an acrylic layer 15 that insures complete covering over of residual fibers and sealing of the surface 7. Such repeat steps are carried out as described and the acrylate resin proportion, as well as the heat applied, may be kept as in the described steps or changed, las desired, for improved results. FIG. l shows means 10, 13 and 14 as repeated to provide an operation that involves three wettings, and, consequently, three singeings and three sandings.

The surface 7, thus sealed ofi, will not spot because the same has high resistance to moisture absorption.

The term acryl-ate resin as used herein is inclusive of all such synthetic liquid resins` that are formed by polymerization of acrylic acid or one of its simple derivatives or mixtures containing these usually with benzoyl peroxide or a similar catalyst.

While the foregoing discloses what is now contemplated to be the best mode of carrying out the invention, the same is, of course, subject to modification without departing from the spirit and scope of the invention. Therefore, it is not desired to restrict the invention to the particular method steps or combination or sequence of method steps described, but to cover all equivalent steps or methods that may fall within the scope of the appended claims.

laying thus described this invention, what is claimed and `desired to be secured by Letters Patent is:

1. A panel-treating process that consists in the successive and continuous steps of wetting the surface of a wood panel with a liquid comprising approximately two percent to five percent `of acrylate -resin in water to swell and raise up the wood bers from the surface of the wood panel, subjecting said raised bers and the panel surface to singeing heat before the liquid penetrates into the panel Iand for a time only sucient -to singe the raised fibers and dry the panel surface without changing the panel color, and nally, sanding said surface to remove the singed fibers while leaving an `acrylate resin coating on said surface.

2. A panel-treating process according to claim l in which said steps are repeated until `the surface is provided with an aorylate resin coating Ithat Completely embeds residual bers on the surface.

References Cited in the file of this patent UNITED STATES PATENTS 1,870,564 Hayden Aug. 9, 1932 2,031,070 Robinson et al Feb. 18, 1936 2,908,590 Norris Oct. 13, 1959 2,973,286 Ulrich Feb. 28, 1961 3,011,988 Luedke et al Dec. 5, 1961 OTHER REFERENCES Hackhs Chemical Dictionary, page A17, McGraw-Hill, New York, 1944. 

1. A PANEL-TREATING KPROCESS THAT CONSISTS IN THE SUCCESSIVE AND CONTINUOUS STEPS OF WETTING THE SURFACE OF A WOOD PANEL WITH A LIQUID COMPRISING APPROXIMATELY TWO PERCENT TO FIVE PERCENT OF ACRYLATE RESIN IN WATER TO SWELL AND RAISE UP THE WOOD FIBERS FROM THE SURFACE OF THE WOOD PANEL, SUBJECTING SAID RAISED FIBERS AND THE PANEL SURFACE TO SINGEING HEAT BEFORE THE LIQUID JKPENETRATES INTO THE PANEL AND FOR A TIME ONLY SUFFICIENT TO SINGE THE RAISED FIBERS AND DRY THE PANEL SURFACE WITHOUT CHANGING THE PANEL COLOR, AND FINALLY, SANDING SAID SURFACE TO REMOVE THE SINGED FIBERS WHILE LEAVING AN ACRYLATE RESIN COATING ON SAID SURFACE. 